Who Are the Biggest Losers: Husbands or Wives?

The Maggios, Grapsys and Sotacks have worked, played and raised kids together for years. Now the couples from Pennsylvania hope to lose weight together in "Good Morning America's" Battle of the Spouses: Wives vs. Husbands Weight Loss Challenge.

While most contestants want to lose weight, the couples will really be engaged in a survival of the fittest. The fittest team, measured by strength, flexibility and body mass composition, will be declared the winner when the teams return to "GMA" on Aug. 24. You can watch their progress each week here.

Strength will be measured by the number of crunches each contestant can do in one minute and the total number of pushups. Flexibility will be measured by how far they can stretch while reaching for their toes seated on the floor. Body mass composition will be measured by a weight and body mass index, reflecting how much weight they are losing and how much muscle they are gaining.

The Players
Mike Maggio, Ron Grapsy and Will Sotack have called themselves "The Brews Brothers." Their biggest obstacles?: beer and their wives' cooking.

Tammy Maggio, Tracie Grapsy and Janine Sotack will compete as "Moms on a Mission." The wives are up against a lack of time, discipline problems and a lack of energy.

Both teams have known each other for years, and know their teammates' strengths and weaknesses. Mike and Ron met in college and currently play together in a cover band, "Double Secret Probation." Tammy and Janine are sisters. They've all been friends for over 20 years.

Dave Zinczenko, editor in chief of Men's Health magazine and author of "The Abs Diet," and Tina Johnson, executive editor of Women's Health will aid the teams on their journeys.

Zinczenko will have the men running and lifting weights, with an emphasis on the leg muscles since 50 percent of the body's muscles are in the legs.

Johnson will have the women focusing on both cardio and weights to achieve "tighter butts, trimmer thighs, flat bellies and toned arms."

The Odds

Zinczenko said the men are at an advantage when it comes to losing weight because testosterone helps build lean muscle mass, which in turn burns more fat. On average, men have 22 percent body fat, and women have 32 percent body fat. To lose the fat women just have to "sweat a little bit more," according to Johnson.

The ladies have their own advantage when it comes to flexibility. In the pre-challenge flexibility assessment in which contestants tried to reach past their toes while sitting, the women averaged 6.7 inches. The men only managed 0.7 inches.

The Brews Brothers are hoping to at least see their toes at the end of the challenge -- even if they can't reach them -- by shedding their beer guts.

Mike Maggio has a plan: lock up his personal keg at home, and "get up with the chickens" and hit the gym before work.

Tammy Maggio said Mike talks a "big game," but hasn't been to the gym all week whereas she's been there three times already.

Tammy likes to work out with a partner, which Zinczenko says increased your odds of sticking with a workout regimen. Johnson added that because women are "social animals," having a workout buddy motivates them and talking while jogging regulates the heart rate.

Win or lose, Tammy Maggio hopes that everyone at least gets healthy. Her husband just turned 40, and they're all getting older. She hopes they'll still be taking vacations together when they're senior citizens.